# DiffiCat (remote · app.difficat.com)

Compare a website before and after a migration: missing pages, content changes, visual diffs.

- Trust score: 67/100 (medium)
- Registry status: active
- Liveness: live
- Owner verified: no
- Last scored: 2026-09-28

## Components

- remote · `app.difficat.com`: 67/100 (this document), [markdown](https://verifymcp.io/servers/com-difficat-difficat/app.md), [page](https://verifymcp.io/servers/com-difficat-difficat/app)

## Channel facts

- Endpoint: `https://app.difficat.com/mcp`
- Transports: `streamable-http`
- Auth: `none`
- Version: `3.22.4`

## Trust breakdown

How this component scores in each security and reliability category. Every signal is checked automatically against the live server, and we only credit what we can confirm. Scores are 0–100 per category. Scoring method: https://verifymcp.io/docs/scoring (what has changed: https://verifymcp.io/docs/scoring/changelog)

Scored 2026-09-28.

- **Endpoint Security**: 66/100
  - The endpoint's TLS certificate is valid, in date, and uses a strong key.
  - Authorisation not fully verified: no authorisation is required to call this server, and 9 tool(s) never declared a destructiveHint. The MCP spec treats an absent hint as destructive by default, so we cannot call this surface safe.
  - HTTPS is enforced; there's no plaintext access path.
  - The HSTS (Strict-Transport-Security) header is present.
  - DNSSEC is configured correctly; the domain's records validate against the full chain to the root.
- **Transport & Reachability**: 100/100
  - Verified streamable-http transport via a live MCP handshake.
- **Schema Quality & AI Usability**: 67/100
  - AI-judged instruction clarity (good).
  - Context-footprint check failed: tool/resource definitions use about 1351 tokens (~150/item across 9 items; 9 tools + 0 resources), over budget; trim descriptions and params.
  - Usage-examples check failed: none of the tools include examples.
- **Stability & Change Management**: 10/100
  - Stability observed for 3 of 30 days with no destabilising changes; credit accrues until the full window elapses.
- **Tool Coverage**: 95/100
  - 100% of tools have a non-trivial description (not blank, and not just the tool's name).
  - 86% of tool parameters carry a description.
- **Tool Safety**: 100/100
  - No prompt-injection markers were found in the server instructions, tool names or descriptions we captured.
  - We read all 9 captured tool definition(s), and no name or description among them implies an irreversible operation.
  - An AI judge read all 9 captured unit(s) of tool text and found none that tries to manipulate the model reading it.
- **Capabilities**: 100/100
  - Implements a supported MCP spec version (2025-11-25); the latest is 2026-07-28.

## Install

### How do I install the DiffiCat MCP server?

DiffiCat is a hosted endpoint at https://app.difficat.com/mcp, so there is nothing to install locally. Ready-made configuration for Claude, Cursor, VS Code, Codex and 5 more is on this page, copied from each client's own documentation.

### Claude

```bash
claude mcp add --transport http com-difficat-difficat 'https://app.difficat.com/mcp'
```

### Cursor

```json
{
  "mcpServers": {
    "com-difficat-difficat": {
      "url": "https://app.difficat.com/mcp"
    }
  }
}
```

### VS Code

```json
{
  "servers": {
    "com-difficat-difficat": {
      "type": "http",
      "url": "https://app.difficat.com/mcp"
    }
  }
}
```

### Codex

```toml
[mcp_servers.com-difficat-difficat]
url = "https://app.difficat.com/mcp"
```

### opencode

```json
{
  "$schema": "https://opencode.ai/config.json",
  "mcp": {
    "com-difficat-difficat": {
      "type": "remote",
      "url": "https://app.difficat.com/mcp",
      "enabled": true
    }
  }
}
```

### OpenClaw

```bash
openclaw mcp add com-difficat-difficat --url 'https://app.difficat.com/mcp' --transport streamable-http
```

### Hermes

```yaml
mcp_servers:
  com-difficat-difficat:
    url: "https://app.difficat.com/mcp"
```

### Netclaw

```json
{
  "McpServers": {
    "com-difficat-difficat": {
      "Transport": "http",
      "Url": "https://app.difficat.com/mcp"
    }
  }
}
```

### Vellum

```bash
assistant mcp add com-difficat-difficat -t streamable-http -u 'https://app.difficat.com/mcp'
```

### Other

```json
{
  "mcpServers": {
    "com-difficat-difficat": {
      "type": "http",
      "url": "https://app.difficat.com/mcp"
    }
  }
}
```

The mcpServers block is a cross-client convention. Remote transports vary, so check your client's docs.

## Changelog

Every change recorded for this component, newest first. Days that predate change tracking, or that we cannot explain, say so: "we were watching and nothing happened" and "we were not watching" are different claims.

### 2026-09-28 (score 67, −1)

- [functional] We updated how we score, so this day's move reflects our rubric, not a change to the server

### 2026-09-27 (score 68, 0)

- [security] Tool “cancel_comparison” rewrote its description, which is the text the model reads
- [security] Tool “get_report” rewrote its description, which is the text the model reads
- [security] Tool “start_comparison” rewrote its description, which is the text the model reads
- [functional regression] Schema quality: 91 → 114
- [functional] Server version: 3.22.6 → 3.25.5
- [cosmetic] “get_report” added an optional parameter “limit”
- [cosmetic] “get_report” added an optional parameter “offset”
- [cosmetic] “start_comparison” reworded the description of “maxPages”
- [cosmetic] “start_comparison” reworded the description of “urls”
- [cosmetic] “start_comparison” made “maxPages” optional

### 2026-09-26 (score 68, +1)

- [functional improvement] Stability: unverified → 0.03
- [functional] Server version: 3.22.4 → 3.22.6

### 2026-09-25 (score 67)

First indexed and scored.

## MCP tools (9)

### `discover_pages` (~130 tokens)

Discover pages

List the pages of Site A (sitemap, robots.txt, or crawl), mapped onto Site B when given. Paid in USDC (the 402 challenge names the network), or from a prepaid balance when the request carries Authorization: Bearer dck_…: 0.05 USD per call.

Input parameters:

- `maxPages` (integer): Stop after this many pages.
- `sitemapUrl` (string): Sitemap to read instead of the fallbacks.
- `sourceUrl` (string, required): Site A (full URL).
- `targetUrl` (string): Site B; pages are mapped onto it when given.

### `capture_screenshot` (~124 tokens)

Capture screenshot

Full-page PNG of one URL. Returns the image (or, for a large one, links.file to fetch with the jobToken) plus a jobId/jobToken for get_screenshot. Paid in USDC (the 402 challenge names the network), or from a prepaid balance when the request carries Authorization: Bearer dck_…: 0.02 USD per call.

Input parameters:

- `auth` (object): HTTP basic auth for the page.
- `url` (string, required): Page to capture (full URL).
- `viewportWidth` (integer): Capture width in px.

### `start_comparison` (~612 tokens)

Start comparison

Compare Site A against Site B on page existence, content and visual regression. Charged upfront. Paid in USDC (the 402 challenge names the network), or from a prepaid balance when the request carries Authorization: Bearer dck_…: 0.02 USD per page for the first 1000 pages and 0.01 USD per page beyond. maxPages is optional: a ceiling, not a reservation. A job is priced on the pages it compares (the urls list, or the pages discovery finds, at most maxPages), the challenge names the count, and there is no page limit. A single-page comparison is a urls list with one pair (preferred), or maxPages: 1 with the page URLs as sourceUrl and targetUrl; either is priced as one page and runs no discovery. One single-page comparison per client address per day is free when the request carries no payment credential and no prepaid key: the response is the normal 201 with sample: true and pagesCharged: 0, and once the allowance is used the same request is challenged as usual. A sample report over three pages, produced by this API, is at https://difficat.com/agents/sample/report.json. The discovery that prices a job without urls is not charged; discover_pages is a separate, optional purchase for callers who want the page list itself. Set maxPriceUsd to refuse a job priced above your budget before any challenge. A settled charge is final: cancelling, a failed job or partial results do not reduce it. recover_comparison returns a job whose result was lost, given the same payment credential. Poll get_comparison, then get_report (paged with offset and limit).

Input parameters:

- `maxPages` (integer): Optional ceiling on the pages compared and charged for. The job is priced on the pages it compares: the urls list, or the pages discovery finds, at most this many. There is no page limit.
- `maxPriceUsd` (number): Optional spend cap in USD. A job priced above it is refused before any challenge, so an auto-paying client is never asked for more.
- `sitemapUrl` (string): Sitemap to discover pages from.
- `sourceAuth` (object): HTTP basic auth for Site A.
- `sourceUrl` (string): Site A, the reference site (full URL). Required unless urls is given.
- `targetAuth` (object): HTTP basic auth for Site B.
- `targetUrl` (string): Site B, the migrated site. Omit to capture screenshots of Site A only.
- `threshold` (number): Visual diff tolerance as a fraction from 0 (exact) to 1: 0.05 means 5%. The web app takes a percentage; the API does not.
- `urls` (array): Explicit page pairs to compare; skips discovery and is priced per pair. One pair is a single-page comparison and needs no sourceUrl.
- `viewportWidth` (integer): Capture width in px.

### `recover_comparison` (~45 tokens)

Recover a paid job

Returns the job or screenshot the payment credential in _meta paid for, with a new jobToken that replaces the old one. For a paid call whose result never arrived. Free.

### `get_comparison` (~65 tokens)

Get comparison status

Status and progress of a job. Free.

Input parameters:

- `jobId` (string, required)
- `jobToken` (string): The jobToken returned when the job was created. Optional when the request carries the prepaid key that paid the job (Authorization: Bearer dck_…).

### `cancel_comparison` (~81 tokens)

Cancel comparison

Stop a running job; the job reports cancelled within a minute, with the pages compared so far in its report. Free.

Input parameters:

- `jobId` (string, required)
- `jobToken` (string): The jobToken returned when the job was created. Optional when the request carries the prepaid key that paid the job (Authorization: Bearer dck_…).

### `get_report` (~159 tokens)

Get report

The finished report: summary over every page, a slice of the per-page results (offset and limit, default 50 a call, at most 5000; nextOffset points at the next slice), and the plain-text report over that slice. limit: 1 returns the summary with one result. Free.

Input parameters:

- `jobId` (string, required)
- `jobToken` (string): The jobToken returned when the job was created. Optional when the request carries the prepaid key that paid the job (Authorization: Bearer dck_…).
- `limit` (integer): Page results to return (default 1000, at most 5000).
- `offset` (integer): Index of the first page result to return (default 0).

### `get_screenshot` (~100 tokens)

Get screenshot

A screenshot PNG named in the report or returned by capture_screenshot; a large one comes back as links.file to fetch with the jobToken. Free.

Input parameters:

- `filename` (string, required): A screenshot filename from the report.
- `jobId` (string, required)
- `jobToken` (string): The jobToken returned when the job was created. Optional when the request carries the prepaid key that paid the job (Authorization: Bearer dck_…).

### `get_balance` (~35 tokens)

Get prepaid balance

The prepaid balance and the last 20 ledger entries of the key the request carries as Authorization: Bearer dck_…. Free.

## Diagnostics

Captured diagnostic sections: TLS, DNSSEC, Authorisation, Transports. The full working is on the page: https://verifymcp.io/servers/com-difficat-difficat/app#diagnostics

## Score history

- 2026-09-28: 67
- 2026-09-27: 68
- 2026-09-26: 68
- 2026-09-25: 67

## Common questions

### What is the DiffiCat MCP server?

DiffiCat is an MCP server listed in the public MCP registry as com.difficat/difficat. Compare a website before and after a migration: missing pages, content changes, visual diffs. This page covers its hosted endpoint (https://app.difficat.com/mcp).

### Is the DiffiCat MCP server safe to use?

DiffiCat scores 67 out of 100 on VerifyMCP. That is a record of what we were able to check automatically, not an endorsement. The category breakdown on this page shows every signal behind the number, including the ones we could not confirm.

### What tools does the DiffiCat MCP server expose?

DiffiCat exposes 9 tools: discover_pages, capture_screenshot, start_comparison, recover_comparison, get_comparison, and 4 more. Their descriptions and schemas cost roughly 1,351 tokens of context every time the server is loaded.

### Does the DiffiCat MCP server require authentication?

No. We connected to DiffiCat without credentials and it answered, so anything it exposes is reachable by anyone who knows the address.

### Is the DiffiCat MCP server still maintained?

DiffiCat is still listed as active in the MCP registry. We last reached this channel on 28 September 2026. Those dates come from our own scans of the registry and the channel itself, not from anything the publisher announced.

## Links

- Remote endpoint: https://app.difficat.com/mcp
- Website: https://difficat.com/agents
- Changelog RSS feed: https://verifymcp.io/servers/com-difficat-difficat/app.xml
- Changelog JSON feed: https://verifymcp.io/servers/com-difficat-difficat/app.json
- HTML version of this page: https://verifymcp.io/servers/com-difficat-difficat/app